28 
INTRODUCTION. 
IV. 
stems of mangroves near high, water mark ; but it would extend this notice 
to too great a length, were I to enumerate all the forms which occur in this 
prolific region. 
COLLECTING AND PRESERVING SPECIMENS. 
I shall here reprint, for the convenience of the student, the substance of some 
directions for collecting and preserving specimens, issued by the Director of the 
Dublin University Museum. 
Marine Algae, as has already been stated, are found from the extreme of high 
water mark to the depth of from thirty to fifty fathoms ; which latter depth is 
perhaps the limit in temperate latitudes ; the majority of deep water species growing 
at five to ten fathoms. Those within the limits of the tidal influence are to be 
sought at low water, especially the lowest water of spring tides ; for many of the 
rarer and more interesting kinds are found only at the verge of low water mark, 
either along the margin of rocks partially laid bare, or, more frequently, fringing 
the deep tide-pools left at low water on a flatfish rocky shore. The northern or 
shaded face of the tide-pool will be found richest in red algae, and the most sunny 
side in those of an olive or green colour. Algae which grow at a depth greater than 
the tide exposes, are to be sought either by dredging ; or by dragging after a boat 
an iron cross armed with hooks, on all shores where those contrivances can be 
applied ; but where the nature of the bottom, or the difficulty of procuring boats, 
renders dredging impossible, the collector must seek for deep-water species among 
the heaps of sea-wrack thrown up by the waves. After storms seaweed sometimes 
forms enormous banks along the coast ; but even in ordinary tides many delicate 
species, dislodged by the waves, float ashore, and may be picked up on the beach in 
a perfect state. The rocky portions of a coast should, therefore, be inspected at 
low water ; and the sandy or shingly beach visited on the return of the tide. In 
selecting from heaps we should take those specimens only that have suffered least 
in colour or texture by exposure to the air ; rejecting all bleached or half melted 
pieces. 
Collectors should carry with them one or two strong glass bottles with wide 
mouths, or a handbasket lined with japanned tin or gutta percha, for the purpose 
of bringing home in sea water the smaller and more delicate kinds. This precaution 
is often absolutely necessary, for many of the red algae rapidly decompose if 
exposed, even for a short time, to the air, or if allowed to become massed together 
with plants of coarser texture. The cooler such delicate species are kept the better ; 
and too many ought not to be crowded together in the same bottle, as crowding 
encourages decomposition; and when this has begun, it spreads with fearful rapidity. 
These Alga3 should be kept in sea water until they can be arranged for drying, and 
the more rapidly they are prepared the better. Many will not keep, even in vessels 
of sea water, from one day to another. 
A common botanist’s-vasculum, or an indian rubber cloth bag, will serve to 
bring home the larger and less membranous or gelatinous kinds ; but even these, if 
left long unsorted, become clotted together, and suffer proportionably. 
